The present invention relates generally to fish finding devices and more particularly to a reversible drive apparatus which rotates the fish finder transducer back and forth in a preselected pattern in a generally horizontal orientation.
Fish finders have been widely used in the past for providing a fisherman with a means of determining both the depth of the water and for locating either single fish, or schools of fish. Such fish finders have incorporated various echo ranging devices which emit a sound from a submerged transducer downwardly from the boat. When the sound beam strikes a fish or the water bottom, it reflects an "echo" back to the transducer. The echo is converted to electrical energy which may then be amplified and displayed on a video screen.
Typically, fish finders are fixed to a mounting member attached to the boat so that the echo ranging device is directed either downwardly or sideways from the boat. The fish finder can only be rotated in this position by the fisherman manually moving the mounting assembly to perform a "sweep" of a given area.
Recently, side-scan fish sonars have entered the market. A side-scan fish sonar is one wherein the transducer or echo ranger is mounted in a manner so that it faces sideways to "see" a plane of water which is somewhat parallel to the plane of the boat. It permits echo sounding in a generally horizontal orientation. An example of such a side-scan fish sonar is the Scout.RTM. Side Finder fish finder manufactured by the Bottom Line Corporation. These side-scan fish finders are typically mounted on the exterior of a propeller housing of a trolling motor. The trolling motor can be manually pivoted by the fisherman by way of a handle, which pivoting causes the fish finder to rotate in a horizontal plane. In order to effectively scan the water ahead of or to the side of the boat, the fisherman must devote time and substantial effort to this scanning motion, thereby decreasing the time spent actually fishing. Thus, a need for an apparatus which moves the transducer in a scanning movement exists.
There have been some attempts to solve the aforementioned problems. U.S. Pat. No. 2,825,884, issued Mar. 4, 1958 describes an echo ranging device in which a sound transducer is mounted in a submersible housing. A gear shaft extends beneath a boat mounting bracket into the housing and drives the transducer by way of a bevel gear drive in a U-shaped movement. A motor causes this reciprocating action by way of a specially configured gearcam arrangement. The bevel gears are mounted in the housing in a manner which does not permit the mechanism to operate sideways. It is also limited in its variability of rotations. Accordingly, the total area read by the sonar transducer is quite small.
Another device for a searching sonar is described in U.S. Pat. No. 4,815,048, issued Mar. 21, 1989, which describes a dual axis transducer assembly in which a sonar transducer is tiltable about a horizontal axis and which can be driven in rotation around a vertical axis. This construction is overly complicated and expensive because it requires two motors to separately drive the transducer around each of the horizontal and vertical axes. Similar to the device mentioned in U.S. Pat. No. 2,825,884, no provision is made for adjusting the rotation of the transducer.
The present invention overcomes the aforementioned disadvantages. The present invention is directed to a selective reversible drive assembly which rotates a side-scan sonar transducer or similar echo-ranging device back and forth automatically in an arc which is chosen by the fisherman. The drive supplied to the sonar transducer is continuous and is driven by a motor, and the drive of the motor is reversed when the sonar transducer reaches the end of the chosen arc by the fisherman and the motor is automatically reversed to drive the sonar transducer back in the opposite direction. This automatic reversal feature is accomplished by positioning a motor drive control member such as a reverse polarity switch, relay or magnetic pulse assembly proximate to a drive gear of the same such that when the drive gear rotates, an actuating means associated therewith actuates the drive control member to reverse the direction of the motor. The actuating means can include a mechanical stop, a magnet or other similar member which can engage the drive control member during rotation of the drive gear.
The drive gear drivingly engages a driven gear which turns the sonar transducer while drive is supplied to it by the drive gear. When energized, the motor rotates the drive gear which rotates the driven gear to rotate the sonar transducer. The rotation of the drive gear and the transducer, continues in a first drive direction until the actuating means contacts the motor or drive control member causing the motor to reverse its drive or rotation. The rotation of the sonar transducer is correspondingly reversed until the actuating means again contacts the drive control member in its returning path. When such contact is effected the motor drive is reversed again back to its original direction.
The actuating means may use either one or more actuators. Where only one actuator is used, a full, reversing 360.degree. is obtained and where two actuators are used, the actuators may be spaced apart on the drive gear in a desired angular spacing which corresponds to the angle which the fisherman desires to sweep with the sonar transducer. Accordingly, the present invention provides the fisherman with a variably selective reversing drive mechanism for a sonar transducer or echo-ranging device.
In another aspect of the present invention, a visual display is associated with the drive housing and includes a plurality of visual indicators which are activated by the driven gear to visually indicate to the fisherman the area which he is scanning. The visual display may be part of the drive housing or it may be a separate structure therefrom interconnected thereto by suitable means.
Accordingly, it is an object of the present invention to provide a reversible drive apparatus for a side scanning fish sonar in which the transducer is driven back and forth in a general horizontal plane beneath the boat.
It is another object of the present invention to provide a fish finder assembly having a selective reversing drive mechanism in which the fish finder transducer automatically sweeps a preselected amount of a horizontal plane without being manually moved by the fisherman.
It is a further object of the present invention to provide a drive apparatus for a side-scan fish sonar transducer, wherein the drive apparatus rotates the fish sonar in a preselected pattern beneath a fishing boat and wherein the preselected pattern can be easily changed by the fisherman.
It is yet another object of the present invention to provide a selectively reversible drive apparatus for a side-scan fish sonar in which the arc swept by the fish sonar is visually indicated on a display member.
It is still another object of the present invention to provide a selectively reversible drive apparatus for a side-scan fish sonar wherein the drive assembly includes a gear train which is driven by a motor and wherein one of the gears includes a mechanical stop member which actuates a drive control sensor to reverse the sonar transducer drive direction.
It is a still further object of the present invention to provide a reversible drive apparatus for a sidescan fish sonar wherein the drive assembly includes a gear train driven by a motor and wherein one gear of the gear train includes one or more repositionable magnets which actuate a drive control sensor to reverse the sonar transducer drive direction.
These and other objects and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.